Fuel cap



FIG. 1 is a top view of the fuel cap, showing our new design;

FIG. 2 is a front elevational view thereof, the rear elevational view being a mirror image thereof;

FIG. 3 is a right side elevational view thereof, the left side elevational view being a mirror image thereof; and,

FIG. 4 is a bottom view thereof.

The broken line showing of environment is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a fuel cap, as shown and described. 